What times what equals 234, but then if you add them you get 31

13*18
x*y =234
x+y=31

we know the 2 # have to be double digits and both between 10-20

find 2 values that * to a number that ends in 4. Those are the ones value

1*4   11 and 14
2*2   12 and 12
3*8   13 and 18

only 13 and 18 add up to 31 and multiply to 234